The present invention relates to a washing apparatus and more particularly to an improvement of a washing apparatus having a pulsator disposed eccentrically on the inside bottom of a spinnable tub.
In a washing apparatus of the type having a pulsator eccentrically disposed on the bottom of the spinnable tub for increasing washing power, a spinnable tub without perforations, at least below the washing liquid level, rotates to cause liquid to be carried upwardly and to be discharged through its upper portion.
With such an arrangement, however, rotation of the spinnable tub, especially when a small amount of materials is washed, forces liquid to rotate as the liquid surface assumes an inverted paraboloid. At this time, a mass of liquid tends to rise on the pulsator and hence to be shifted off-center more toward the pulsator. Thus, the spinnable tub, while rotating with liquid therein, has a shifted center of gravity, which is a source of abnormal vibrations to which the spinnable tub is subjected. This phenomenon is considered to take place when the spinnable tub is driven to rotate at a speed different from that of rotation of the liquid caused by the spinnable tub, and with such relative rotation between the spinnable tub and the liquid, the projecting pulsator acts as a resistance to the rotating mass of liquid, which is slowed down and rises on the pulsator. The marked tendency to rotate with abnormal vibrations is seen when a small amount of materials is to be washed in the spinnable tub. The conventional washing apparatus of the aforesaid type, therefore, generally has an excessive expenditure for the supporting mechanism to absorb such abnormal vibrations due to the displaced mass of liquid. Furthermore, considering that a flatter pulsator is disposed at the bottom of the spinnable tub to eliminate this problem, this results in a decrease in washing power.